The invention relates to the field of imaging systems, and particularly relates to imaging systems in which a continuous web of media is fed through an imaging apparatus. Imaging systems that feed recording media through an imaging apparatus may include a movable optical carriage that displaces a beam of light from an imaging source, such as a laser. The carriage moves in a direction transverse to the direction of movement of the web in a slow scan to expose a supply of recording media to the light beam. Such a carriage for use in an imaging system including an internal imaging drum for supporting the recording media, is disclosed for example in U.S. Pat. No. 5,598,739, the disclosure of which is hereby incorporated by reference.
As shown in FIG. 1, in a conventional imaging system 10 including an imaging drum 12, a web of image recording media 14 travels from a supply cassette 16 around the inner support surface 18 of the drum 12 to a take up cassette 20. The media generally has sufficient inherent stiffness that it maintains the cylindrical shape of the inner surface 18 of the drum 12 when coupled to cassettes 16 and 20. A movable carriage 22 may be used to position a beam of laser light 24 on desired portions of the recording surface 26 of the media 14. The imaging system 10 is typically coupled to a computer controlled image processor (not shown). The media is typically driven through the system by drive rollers 28 and 30.
Each cassette is typically sealed from light as appropriate, and each provides an elongated opening through which the web of media may pass as it exits the supply cassette 16 and enters the take up cassette 20. The cassettes may be loaded into the system via access openings and/or by removing a top cover. During use, the media is advanced from the supply cassette 16, around the drum surface 18, and up to the take up cassette 20. The take up cassette 20 receives the media and typically includes an active take up roll around which the media is typically wrapped.
The take up (or media receiving) cassette may include a mechanism for grasping the leading edge of the media as it enters the receiving cassette 20. A conventional technique for grasping the leading edge of the media involves providing a core that includes a portion that opens when the core is rotated in the reverse direction, and closes on the media when the core is rotated in the forward direction. It is necessary to ensure proper alignment of the core opening and the approaching leading edge of the media. Such mechanisms, however, are relatively mechanically complex, which results in increased manufacturing cost and increased potential risk of mechanical failure.
There is a need, therefore, for a media receiving cassette that is effective to grasp media, and efficient and economical to manufacture.
The invention provides a media receiving cassette for use in a system in which a web of media is transferred from a supply cassette, through an imaging region, to the receiving cassette. The media receiving cassette includes a housing, a rotatable core, and a spring biased grasping mechanism. The housing includes first and second opposing ends, and at least one of the ends includes a generally circular track therein that includes an extended portion which extends radially outwardly. The rotatable core is coupled to the first and second opposing ends of the housing such that an axis of rotation of the core extends through each of the first and second ends. The spring biased grasping mechanism is attached to the rotatable core via at least one spring. The grasping mechanism includes a tracking member that engages the generally circular track such that the grasping mechanism is permitted to move radially outwardly away from the core when the tracking member is positioned in the extended portion of the generally circular track to thereby permit the media to be received in the core. The grasping mechanism is permitted to move radially inwardly toward the core when the tracking member is positioned in a location other than in the extended portion of the generally circular track.